With engines which utilise an expanding fluid to drive an output shaft, it is common to have a working chamber which varies in volume upon expansion of the fluid. The working chamber is usually defined between wall surfaces, at least one of which is movable relative to the other wall surfaces to facilitate transmission of the power generated by the expanding fluid to an output shaft. The need for wall surfaces movable relative to each other introduces problems, one being associated with sealing between such surfaces and another being frictional losses.
The present invention seeks to provide a rotary engine which does not utilise a working chamber of variable volume. In this way the invention seeks to limit sealing problems and frictional losses which are common with conventional rotary engines and internal combustion engines generally.